How to Implement Redux in 24 Lines of JavaScript

Redux is among the most important JavaScript libraries ever created. Inspired by prior art like Flux and Elm, Redux put JavaScript functional programming on the map by introducing a scalable architecture of three simple points.

Whenever someone subscribes to our store, they get added to the listeners array. The is important because every time someone dispatches an action, all the listeners must be notified in a loop.

Calling yourReducer with undefined and an empty object returns the initialState we installed up above. This gives us a proper value to return when we call store.getState(). Speaking of which, let's create that method.

store.getState()

This is a function that returns the latest state from the store. We'll need this to update our UI every time the user clicks a button.

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